Field of the Invention
The present disclosure relates to a double-lip seal of a pneumatic spring brake chamber for a vehicle, and more particularly, to a double-lip seal of a pneumatic spring brake chamber for a vehicle with increased sealing performance between an inner circumferential surface of a through-hole of an adaptor housing and an outer circumferential surface of an actuator rod to prevent fluid leakage.
Description of the Related Art
Large vehicles such as buses, trucks, trailers, and other heavy machinery use a brake chamber for vehicles that performs delicate and fast braking operation while high-speed driving or parking and has good braking performance.
Seeing the structure of a vehicle brake chamber, the vehicle brake chamber includes a head housing, an adaptor housing and a bottom housing of a hollow shape in a sequential order from the top. On the other hand, a piston is placed between the head housing and the adaptor housing, and a hollow actuator rod is connected to the piston and placed through a through-hole of the adaptor housing. A diaphragm is placed between the adaptor housing and the bottom housing. Furthermore, a pressure plate supporting the diaphragm and a push rod supporting the pressure plate are provided, and the push rod is placed through the through-hole formed in the bottom housing.
In this instance, a space formed between the head housing and the piston is a spring chamber, and a spring is placed therein. A space provided between the piston and the adaptor housing is a pressure chamber. A space formed between the adaptor housing and the diaphragm is a service chamber, and a push rod chamber is formed between the diaphragm and the bottom housing.
As described above, the vehicle brake chamber is composed of the spring chamber, the pressure chamber, the service chamber, and the push rod chamber from top to bottom, and as the pressure plate moves up and down by adjustment of the elastic force of the spring and the air pressure in the service chamber, the push rod connected through the lower end of the bottom housing is moved, allowing the brake to operate while the vehicle is driving or parked.
In this instance, a sealant is applied between the inner circumferential surface of the through-hole of the adaptor housing and the outer circumferential surface of the actuator rod to prevent air from leaking. However, the conventional sealant has a weak contact force with the inner circumferential surface of the through-hole of the adaptor housing and the actuator rod, resulting in reduced sealing function, and impurities entering the housing may push the contacted part of the sealant, causing degradation in sealing performance.